Do you know about Charles Howard Hinton? He's one of those strange Victorian characters. He coined the word "tesseract" for a 4-dimensional cube - a word mainly used by SF writers, not mathematicians. But that's just the beginning.

In his 1888 book A New Era of Thought, he advocated the spiritual benefits of visualizing 4-dimensional geometry. In his later book The Fourth Dimension, he developed a system of colored cubes to help people do this.

Rumors subsequently arose that these cubes drove than one person insane.

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